An apparatus for flanging and swaging a cylindrical can body on both ends, especially an aerosol spray or beverage can, can comprise at least two flanging and swaging heads for receiving the can body held on a rotatably driven spindle slidable axially opposite each other into the can body.
The flanging and swaging heads each have a radially slidable wobbler abutting on one side centrally on a conical piece slidable axially against an inner spring. Each flanging and swaging head is associated with a pivoting arm equipped with a flanging and swaging roller which is pivotable by at least one cam about an axis parallel to the rotation axis of the spindle so that the flanging and swaging roller is brought into and out of engagement with the wobbler for formation of the flanged and indented edge of the can body by radial displacement of the wobbler.
This apparatus which is described in the brochure: Lanico "Bordel- and Einziehautomat BEA 6-325" (Lanico Prospectus, "Flanging and swaging Unit BEA 6-325") is a completely automatic unit in which the can bodies are fed through the machine with their axes horizontal. Several work stations or biting like planets with the flanging and swaging heads slidable in opposite directions into the can bodies and associated pivoting arms and cams are provided.
During formation of the indented and flanged edges, the can bodies are thrust laterally by the counterpressure and the radial yielding motion of the wobbler in contrast to the aligned longitudinal axes of the flanging and swaging head engaged in the can body and/or of the associated spindle. When an indented flanged edge is made only on one end of the can body, while the other can end is shaped or deformed to provide an unindented or only slightly swaged flanged edge, the can body assumes an inclined position relative to the longitudinal axis of the cooperating spindle.
The can body is not guided exactly during the described displacement and/or inclined position by the yielding of the wobbler disk and/or the wobbler disks and the flanging and swaging rolls acting on the can body and the wobbler at one place on the can circumference.
To assist in guiding a bell can be provided in the form of a ring structure axially behind the wobbler on the spindle which provides a bell like annular surface facing the edge of the can body. The front edge of this can body supports itself on this annular surface during the first part of the deformation of the can body end so that the yielding of the can body during one part of the deformation of its edge region is kept in certain bounds.
However it is not possible to keep guiding the can body during the entire flanging and swaging process by this abutting member bell so that despite the abutting member bell the formation of the flanged and indented edges of the can body are made only with comparatively large variations or tolerances over the entire circumference of the individual can and also from can to can.
These variations occur especially in can bodies which are made from a hard metal sheet. With this hard material in the apparatus known up to now the unavoidable and variable resiliency of the materials in the region of the flanging and swaging head acts so that it has been impractical up to now to use a hardened metal sheet, especially a doubly reduced metal sheet, for making the can body although metal sheet of the hardened type is economical and can be used in a substantially thin walled form for the can body. Up to now the metal plate or sheet used for this type of can body has been only slightly hardened.